The New York Times tech Q&A explains how to enable and disable programs from starting automatically on your PC and Mac. This section is usually pretty elementary (especially for you, Smartypants), but this one includes a simple Mac tidbit I never noticed before:

If one of the programs you want to add is already in your Mac's Dock, you can also control-click (or right-click if your mouse has multiple buttons) on the desired icon and choose the "Open at Login" option from the menu.